The present disclosure relates generally to valves and associated systems and methods. In some instances, embodiments of the present disclosure are configured to be part of an intraocular pressure (IOP) control system for use in ophthalmic treatments.
Glaucoma, a group of eye diseases affecting the retina and optic nerve, is one of the leading causes of blindness worldwide. Most forms of glaucoma result when the IOP increases to pressures above normal for prolonged periods of time. IOP can increase due to high resistance to the drainage of the aqueous humor relative to its production. Left untreated, an elevated IOP causes irreversible damage to the optic nerve and retinal fibers resulting in a progressive, permanent loss of vision.
FIG. 1 is a diagram of the front portion of an eye that helps to explain the processes of glaucoma. In FIG. 1, representations of the lens 110, cornea 120, iris 130, ciliary body 140, trabecular meshwork 150, and Schlemm's canal 160 are pictured. Anatomically, the anterior segment of the eye includes the structures that cause elevated IOP which may lead to glaucoma. Aqueous humor fluid is produced by the ciliary body 140 that lies beneath the iris 130 and adjacent to the lens 110 in the anterior segment of the eye. This aqueous humor washes over the lens 110 and iris 130 and flows to the drainage system located in the angle of the anterior chamber 170. The angle of the anterior chamber 170, which extends circumferentially around the eye, contains structures that allow the aqueous humor to drain. The trabecular meshwork 150 is commonly implicated in glaucoma. The trabecular meshwork 150 extends circumferentially around the anterior chamber. The trabecular meshwork 150 seems to act as a filter, limiting the outflow of aqueous humor and providing a back pressure that directly relates to IOP. Schlemm's canal 160 is located beyond the trabecular meshwork 150. Schlemm's canal 160 is fluidically coupled to collector channels (not shown) allowing aqueous humor to flow out of the anterior chamber. The two arrows in the anterior segment of FIG. 1 show the flow of aqueous humor from the ciliary bodies 140, over the lens 110, over the iris 130, through the trabecular meshwork 150, and into Schlemm's canal 160 and its collector channels.
One method of treating glaucoma includes implanting a drainage device in a patient's eye. The drainage device allows fluid to flow from the anterior chamber of the eye to a drainage site, relieving pressure in the eye and thus lowering IOP. In order to provide desired treatments to patients, it may be important to regulate the flow of aqueous humor through the drainage device. Drainage devices with flow regulation devices, however, may be large and unwieldy when implanted in the eye. Such devices may present various complications, including, without limitation, discomfort to the patient and tissue irritation. Therefore, it may be desirable to provide flow regulation devices in a smaller package more suitable for implantation in the eye.
The system and methods disclosed herein overcome one or more of the deficiencies of the prior art.